Forgot to mention that I'm in western Tennessee and plant hardiness zone 7B

Terry,the exact time to rebloom is hard to predict and severely affected with newly planted shrubs. Wholesalers made the plant awaken at "the wrong time" so the plant would be blooming as soon as the nursery put it on sale. So, give it more time and do not prune. It may surprise you later on when the temps have gone down.

The spots are a common fungal infection called leaf spot or Cercospora Leaf Spot. Usually caused by the presence of the fungi and by overhead watering (manually or by sprinklers).

Common "clean sanitary" suggestions: Try to water early in the morning only and water the soil, never the leaves. Clear any plant debris from under the shrub. Do not overwater so the area is not humid. Separate the shrubs from others to improve air flow between plants. Pick up leaves/blooms that fall and throw them in the trash. Do the same when the shrub goes dormant in the fall. Do not add the leaves/blooms to the compost but throw them in the trash instead. Drought and low humidity suppresses the problems until late summer so it is common to see it start to crop up more now.

You can cut the most affected leaves if aesthetically unpleasing; not sure if the plant will develop a replacement now or wait until Spring. You can also apply fungicides but since the shrubs are about to go dormant soon anyway, it is tough to decide if you want to buy $$$ the fungicides and use them or not. For effective control with a fungicide, apply it as soon as the leaf spots are detected. So you could apply them now and earlier in the season next season.

See below for suggested fungicides. Browse down to where it talks about cercospora leaf spot.

http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf

Luis

I live in Southern Pennsylvania. I have a three year old endless summer that has been healthy and blooms beautifully. This past summer it was affected with the same type of fungus described above. I am a fanatic about cleaning my tools and hand watering at the root perimeter base of the plant not overhead. I am perplexed as to how the fungus began. I sprayed neem oil twice but the hydrangea does not look happy. Now that it is almost December, does anyone have a suggestion - should I simply clear the fallen debris, prune back the shrub or? I am worried about it awakening in the spring with the fungus intact.

Re: awaken with the fungus intact: leaf spot currently does not have a cure so the most you can do once the shrub has it is to use good housekeeping techniques such as never water the leaves (water the soil early in the mornings instead), keep the area under the shrub "clean" of plant material (leaves, etc), replace the mulch if the infestation is large, cut the dried out leaves' petiole and throw the leaves in the trash, deadhead the blooms and dispose also in the trash, do not over-water (this keeps the humidity high) and improve air flow between plants (this reduces humidity). You CAN ALSO use fungicide but the recommended fungicides controls it and does not cure it; see the link info about the fungicides. It is soooo late in the growing season now for you that you may be better off using the fungicide next year and apply it as suggested in the links. Note that if you cut the leaves at the petiole or if you deadhead (not the same as pruning, you will not break dormancy; the link below talks about deadheading under the section titled 'Removing Old Blooms': http://hydrangeashydrangeas.com/pruning.html

Thanks much to luis_pr!

You're welcome. Happy Thanksgiving. I have this issue on a few shrubs myself and I try to control it with those suggestions. It becomes visible in the Fall but it really is present before that. I tried those techiniques first and minimized the bad look when the spots become visible (cut s-o-m-e leaves off IF they look pretty bad).